Hollow piston hammer



Sept. 19, 1933. G, M NELL ET AL HoLLow PIsToN HAMMER Filed March 2o,1930 IN V EN TORS` Gascn/e /14 /Ve// foward 14./ fiere/75 of. @wwwATTORNEY.

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Patented Sept. 19, 1933 UNITED STATES HOLLOW PISTON HAMLIER Gustave M.Nell and Edward W. Stevens, Detroit. Mich., assignors to ChicagoPneumatic Tool Company, New York,

New Jersey N. Y., a. corporation of Application March 20, 1930. SerialNo. 437,358

14 Claims.

This invention relates to percussive machines and more particularly tostationary machines adapted for metal drawing and similar operations.

One object of the invention is to provide a percussive machine forpassing the work axially therethrough. Another object is to protect theoperative parts of the machine from interference by the work whilefacilitating its passage. Other objects will be apparent from thedetailed description which follows.

The invention involves a percussive machine having a hollow piston withthe work passing axially therethrough. The piston may be arranged toreciprocate between the inner and outer walls respectively of twocylinders coaxially mounted one within the other. The work is acted uponby a die which is subjected to the blows of the piston and when an innercylinder is used the work passes through the bore -of the latter.Suitable means, which may include the die, support the cylinders fixedlyin proper relation to one another to insure theV functioning of thepercussive motor. Y

In order to illustrate the invention concrete embodiments thereof areshown in the accompanying drawing in which:

Fig. 1 is a longitudinal sectional view somewhat diagrammatic incharacter of a fluid pressure valveless percussive tool; and

Fig. 2 is a similar longitudinal sectional view showing atvalved fluidpressure hammer.

Both forms of the invention disclose a percussive machine adapted topass the work in solid extended form, such as a metal rod, axiallythere-l through while subjecting the same to drawing' or similaroperations through the vibratory action produced by a high speedpercussive member upon a die in engagement with the work.

In the form shown in Fig. 1 a cylinder 3 has reciprocably mountedtherein a hollow or annular piston 4 for imparting blows directly to ahollow or annular die 5 also telescoping at least partially intocylinder 3 and movably supported by the same. Motive fluid is admittedcontinuously through inlet port 6 in cylinder 3 to an annular chamber inpiston 4 providedby groove or recess 'when die 5 strikes abutment 15.

ent invention. Fig. 1 shows the piston at the beginning of its rearwardor return stroke. The pressure fluid enters the inlet port 6 and passesby way of annular groove 7 and passage 9 to the front end of the pistonchamber. The piston 4 is thereby driven rearwardly, the exhaust air atthe rear end of the chamber passing through exhaust port 10. During therearward movement of the piston, port 10 becomes covered, therebyeffecting the compression of uid at the rear end of the chamber, buttheV piston continues until some time after the annular groove 7 has cutoff the supply of motive huid from the passage 9 and has diverted theiiuid through passage 8 to the rear end of the chamber. When the port 11is uncovered, the pressure at the front end of the piston chambersuddenly drops, and the piston is caused to move in the forwarddirection. The forward movement of the piston is similar to the rearwardmovement and will continue until the port 10 is uncovered.Y

In order to protect the hammer mechanism against interference by thework passing axially through the machine an inner cylinder 12 is pro'vided coaxially disposed within outer cylinder 3 and having slidingengagement with the inner surfaces of piston 4 and die 5. The latter maybe utilized to maintain cylinders 3 and l2 in proper co-axial relationat one end. Suitable means for the same purpose at the opposite end maycomprise a radial flange on one of the members of greater lateral extentthan the piston chamber. In the form shown inner cylinder l2 has flange12a which seats in an annular recess 3a in cylinder 3 but projectsbeyond the latter to be en" gaged by a perforated back head 13.` Inorder that the latter may be accurately centered to provide anaxialpassage for the work it may have an annular recess 13a receiving theprojecting portion of flange 12a. Side rods 14 may be utilized to holdback head 13 in place. These rods may serve resiliently to support atransverse retainer abutment 15 for limiting the movement of die 5 inthe machine and to prevent its accidental ejectment therefrom. To thisend rod 14 may have sleeved. thereover spacers 16 interposed betweenabutment 15 and perforated ears 3bA on outer cylinder 3. Coil springs 17on rods" 14 beyond abutment 15 and backed by securing members, such asnuts 18, prevent breakage of parts An annular buffer member 19 ofleather, or rubber compound, may be suitably mounted as in a groove onabutment 15 to take the 'direct blow of die 5.

In the modification shown in Fig. 2 a machine of less overall length isprovided in which the distribution of motive fluid to effect thereciprocations of hollow piston 20 is controlled by anautomatically-thrown distributing valve 2l. While the valve may be ofany suitable or known type, it is herein disclosed as a ring valve.Valve 21 is supported in a valve block comprising a case 22 and cylinderclosure disc 23, the latter having a passage 24 opening directly intothe rear end of the piston chamber and also a portion of passage 25leading through the wall of outer cylinder 26 to the front end of thepiston chamber. Flange 27a on inner cylinder 27 serves as the lid forthe valve case and is engaged directly by perforated back head 28 whichis secured to outer cylinder 26 by a threaded connection and providesthe inlet 29 for the motive fluid. Valve 21 distributes the motive fluidin alternation to passages 24 and 25 to reciprocate piston 20 in amanner well known to those skilled in the art. The incoming motive fluidis conducted from inlet 29 through radial openings (not shown) in thecase 22 to the top and bottom peripheral surfaces of the ring valve 2l.In the position shown in Fig. 2, the valve is on its upper seat therebyclosing the passage 25 but permitting fluid to flow through passage 24to the rear end of the piston chamber. The fresh supply of motive fluidnow engages a larger area of the bottom of the valve than the tcp of thesame, and thereby tends to hold the valve in the position shown. Thepiston 20 is caused to move forwardly pushing the exhaust air in thefront end of the piston chamber through outlet 31 until this outlet iscovered by the piston 20. Thereafter, continued forward movement of thepiston compresses the iluid in the forward end of the chamber until asufficient pressure is reached to throw the valve 21 downwardly due tothe pressure transmitted through passage 25 to the front end of thepiston chamber and forces the piston rearwardly until the valve isthrown back to the position shown in Fig. 2. Outer cylinder 26 hasatmospheric piston-controlled vents 30 and 31 for the opposite ends ofthe piston chamber and long perforated ears through which extend bolts32 with spacers 33 thereon for supporting retainer abutment 34 formovable die 35. Retainer abutment 34 conforms in all respects toabutment 15 of the first form of the invention having springs 36supporting the same and a cushion ring 37 to receive the direct blow ofdie 35. In operation the work in the form of a bar, rod, or tube to beextruded or reduced by die 5 or 35, enters the machine through the borein the retainer abutment 15 or 34, it being understood that the Work maybe forced through the machine or the machine moved over the work whilethe latter is heldstationary. In either instance, as the Work enters thedie 5 or 35 the percussive motor is operated, and the blows rained upondies 5 and 35 by the reciprocating hammer piston 4 or 20 produces rapidaction of the die upon the work so that the finished work may passthrough the machine with a steady continuous movement. The rapid actionof the machine is enhanced by the mounting of die 5 or 35 whereby slightmovement of the same Within the machine in an axial direction ispermitted. Inner cylinder 12 or 27 serves as a guide for the work andmaintains it out of any possibility of contact with percussive member 4or 20 so that the machine cannot be injured by its accidentaldisplacement relative to the work.

While the invention has been herein disclosed in what are now consideredto be preferred forms,

2. A percussive machine having a hollow piston I reciprocable therein, adie movably mounted in said machine to receive the blows of said piston,and means for guiding the work acted upon by said`die axially throughsaid machine and piston but maintaining it out of contact with saidpiston.

3. A percussivev machine having a hollow piston reciprocable therein, adie movably mounted in said machine to receive the blows of said piston,resilient means for limiting the movement of said die in one direction,and means for guiding the work acted upon by said die axially throughsaid machine but maintaining it out of contact with said piston.

4. A percussive machine comprising tubular members in coaxial relationproviding a central passage therethrough and an annular chambertherebetween, a hollow piston reciprocable in said chamber, and meanssubjected to the blows of said piston for acting upon work passingthrough said passage.

5. A percussive .machine comprising tubular members, means maintainingsaid members in fixed co-axial relation to provide a central passagetherethrough and a chamber therebetween, a piston reciprocable in saidchamber, and a die supported by one of said members in position toreceive the blows of said piston for working upon material passingthrough said passage.

6. A percussive machine comprising tubular members in co-axial relationproviding a central passage therethrough and an annular chambertherebetween, a hollow piston reciprocable in said chamber, meanssubjected to the blows of said piston for acting upon work passingthrough said passage, and means maintaining said members in fixedco-axial relation including a flange on one of said members.

7. A percussive machine comprising tubular members, means maintainingsaid members in fixed co-axial relation to provide a chambertherebetween including a flange on one of said members of greaterlateral extent than said chamber, a piston reciprocable in said chamberand a die for receiving the blows of said piston.

y8. A percussive machine comprising tubular members, means maintainingsaid members in fixed co-axial relation to provide a chambertherebetween including a radial flange on said inner memberof greaterextent than said chamber, a piston reciprocable in said chamber, anda.die for receiving the blows of said piston.

9. A percussive machine comprising two cylinders co-axially mounted onewithin the other,

means maintaining said cylinders in xed relation including a ange on onemember, an annular piston reciprocable in the chamber provided betweensaid members, a die movably supported by both cylinders for receivingthe blows lof said piston, and resiliently mounted retainer abutment forlimiting the outward movement of said die. l

10. A percussive machine comprising tubular members, meansmaintainingsaid members in xed co-axial relation to provide a chambertherebetween including a radial ange on said inner member of greaterextent than said chamber, a back head engaging said harige, a pistonreciprocable in said chamber, and a die for receiving the blows of saidpiston.

l1. A iluid pressure percussive machine comprising two cylindersco-axially mounted one within the other to provide a piston chambertherebetween, an annular piston reciprocable in said chamber, means fordistributing pressure fluid to the opposite ends of the piston chamberto reciprocate said piston, means at one end of said machine formaintaining said cylinders in proper spaced relation, a die at theopposite end of said machine for maintaining the spacing of saidcylinders and for receiving the blows of said piston.

12. A iluid pressure percussive machine, comprising two cylindersco-axially mounted one within the other to provide a central passagetherethrough and a piston chamber therebetween, an annular pistonreciprocable in said chamber, a valve block at one end of said machinehaving ports and passages leading to the opposite ends of said chamber,an automatically-thrown distributing valve for controlling said portsand passages, one of said cylinders having a radial flange forming a lidfor said valve block, and a die at the opposite end of said machine forreceiving the blows of said piston and for maintaining the coaxialrelation of said cylinders.

13. A fluid pressure percussive machine comprising two cylindersco-axially mounted one within the other to provide a central passagetherethrough and a piston chamber therebetween, an annular pistonreciprocable in said chamber, a valve block at one end of said machinehaving ports and passages leading to the opposite ends of said chamber,an automatically-thrown distributing valve for controlling said portsand passages, said inner cylinder having a radial flange forming a lidfor said valve block, and a die at the opposite end of said machine forreceiving the blows of said piston.

14. A iiuid pressure percussive machine comprising two cylindersco-axially mounted one within the other to provide a central passagetherethrough and a piston chamber therebetween, an annular pistonreciprocable in said chamber, a valve block at one end of said machinehaving ports and passages leading to the opposite ends of said chamber,an automatically-thrown distributing valve for controlling said portsand passages, said inner cylinder having a radial ange forming a lid forsaid valve block, a back head secured to said outer cylinder andengaging said flange for maintaining the parts at the valve end of themachine in proper assembled relation, and a die at the opposite endslidably engaging and spacing both cylinders for receiving the blows ofsaid piston.

GUSTAVE M. NELL. EDWARD W. STEVENS.

CERTIFICATE OF CORRECTION.

Patent No. l, 927, 499.

September 19, 1933.

GUSTAVE M. NELL, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Page 3, line 88, claim 13, after "piston" insert "and .for maintainingthe co-axial relation of said cylinders"; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 24th day of October, A. D. 1933.

(Seal) F. M. Hopkins Acting Commissioner of Patents.

